A GH 134 beta-1,4-mannanase SsGH134 from Streptomyces sp. NRRL B-24484 possesses a carbohydrate binding module (CBM) 10 and a glycoside hydrolase 134 domain at the N- and C-terminal regions, respectively. Recombinant SsGH134 expressed in Escherichia coll. SsGH134 was maximally active within a pH range of 4.0-6.5 and retained >80% of this maximum after 90 min at 30 degrees C within a pH range of 3.0-10.0. The beta-1,4-mannanase activity of SsGH134 towards glucomannan was 30% of the maximal activity after an incubation at 100 degrees C for 120 min, indicating that SsGH134 is pH-tolerant and thermostable beta-1,4-mannanase. SsGH134, SsGH134-Delta CBM10 (CBM10-linker-truncated SsGH134) and SsGH134-G34W (substitution of Gly34 to Trp) bound to microcrystalline cellulose, beta-mannan and chitin, regardless of the presence or absence of CBM10. These indicate that GH 134 domain strongly bind to the polysaccharides. Although deleting CBM10 increased the catalytic efficiency of the beta-1,4-mannanase, its disruption decreased the pH, solvent and detergent stability of SsGH134. These findings indicate that CBM10 inhibits the beta-1,4-mannanase activity of SsGH134, but it is involved in stabilizing its enzymatic activity within a neutral-to-alkaline pH range, and in the presence of various organic solvents and detergents. We believe that SsGH134 could be useful to a diverse range of industries. (C) 2017, The Society for Biotechnology, Japan. All rights reserved.